Pilot studies demonstrate that the electrophysiological processes associated with flash stimulation in the CNS of the rat, as evidenced by the recording of an evoked potential, can also be detected and recorded using ultra high frequency electro-magnetic fields (UHFEMF). The amplitude distribution of an applied UHFEMF is changed in a dynamic fashion by the electrophysiological processes of the rat brain. This change in amplitude can be recorded and averaged in a similar fashion to the electrical potentials of the rats CNS. The waveform generated by the changing amplitude of the UHFEMF shows striking correlations with the standard evoked potential. A large body of research has shown that UHFEMF when amplitude modulated at physiological frequencies (1-50 hz) has specific effects upon CNS electrophysiological function. This pilot data is the first study of the effects of CNS electro-physiological processes on the physical properties of UHFEMF fields themselves. To validate that the UHFEMF technique is recording physiological activity the methodology must prove reliable and be able to detect relatively small changes in amplitude and latency of electrophysiological processes under varying conditions. This would eliminate movement artifact or electromagnetic artifact from the flash stimulation equipment as sources of the UHFEMF wave forms in the preliminary results. It is the intent of this project to replicate the preliminary data using higher stability UHFEMF generating equipment and varying flash intensities and duration of time between stimulations. If the UHFEMF technique shows reliably high correlations with the varying amplitudes and latencies of the flash evoked potential in this experimental design then artifact is excluded. Besides replicating and validating the pilot data this project promises to yield information about the neurophysiological mechanisms that are involved in the interaction of CNS function and electromagnetic fields. It will also explore the sensitivity of the UHFEMF recording technique and its possible use in recording subcortical CNS electrophysiological activity noninvasively.